NIR spectroscopic monitoring of resin-loading during assembly of engineered wood product

ABSTRACT

Calibrating near infra red (NIR) spectroscopic instrumentation for quantitative measurement of resin-loading of prepared wood materials, as moving in an assembly-forming line, for subsequent pressing under heat and pressure for manufacture of engineered-composite wood product. Feedback of measured data of resin-loading, during in-line assembly operations, enables maintaining consistent resin-loading and optimizes resin usage. Calibration of NIR spectroscopic instrumentation can be carried out on equipment simulating in-line movement of pre-established reference-source test-samples; or, can be carried out during on-line movement of wood-material test samples. The developed calibration method removes absorptive effects at wavelengths for constituents other than resin, such as the moisture content of the wood-materials and of the resin, while maintaining accurate and prompt NIR spectroscopic measurements of resin-loading in a continuous assembly line.

This invention relates to use of near infrared (NIR) and spectroscopicinstrumentation for measuring resin-loading of wood-materials duringassembly-line movement in order to achieve resin-loading results withinmanufacturing standards for subsequent production of composite woodproduct. In one of its specific aspects this invention is concerned withcalibrating NIR spectroscopic instrumentation for quantitative analysisof resin-loading of wood-strand materials.

OBJECTS OF THE INVENTION

Objects of primary importance involve uncovering methods for using nearinfrared (NIR) radiation and spectroscopic technology for quantitativemeasurement of resin-loading of wood-materials while traveling in-linefor assembly of engineered wood product; so as:

-   -   (a) to achieve homogeneity of engineered wood product,    -   (b) to maximize production of engineered wood product within        desired manufacturing specifications, and    -   (c) to optimize resin usage.

A related important object involves calibration of NIR spectroscopicinstrumentation to enable measuring resin-loading of wood-materialswhile being moved to simulate movement in a continuous-type assemblyline.

A related object includes assembly-line resin-loading verificationinvolving feed-back of resin-loading information as measured bycalibrated NIR spectroscopic instrumentation so as to maximizecontinuity of assembly operations for subsequent production of compositewood-strand product within desired manufacturing specifications.

The above and other objects and contributions of the invention aredisclosed in more detail during description of the invention in relationto the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic perspective view of an embodiment of the inventionfor calibrating NIR spectroscopic measuring instrumentation, and fortraining of those calibration principles;

FIG. 2 is a diagrammatic presentation for describing steps incalibrating NIR spectroscopic measuring instrumentation in accordancewith the invention;

FIG. 3 is a graphical presentation verifying quantitative calibrationresults of NIR spectroscopic instrumentation in accordance with theinvention;

FIG. 4 is a flow chart for describing concepts for NIR spectroscopiccalibration and correlating with on-line resin-loading operations forassembly of wood-materials, in accordance with the invention;

FIG. 5 is a diagrammatic presentation for describing on-line equipmentfor preparing and handling wood-strand materials and carrying outon-line resin-loading of those wood-materials using calibrated NIRspectroscopic quantitative-analyses of the invention, including use offeed-back information, as measured on-line, for maximizing continuingresin-loading within desired manufacturing specifications;

FIG. 6 is a schematic view for describing control of resin-loading ofdistinct individual wood strand layers, in accordance with theinvention, for completing subsequent bonding of compositeoriented-strand-board;

FIG. 7 is a top plan view for describing an external face surface of OSBas assembled using NIR spectroscopic measurement of resin-loading inaccordance with the invention;

FIG. 8 is a front-elevation view of the OSB of FIG. 7, for describingassembly of resin-loaded individual wood-strand layers in accordancewith the invention, as subsequent pressed and bonded to producecomposite oriented-strand-board of the invention; and

FIG. 9 is a perspective view for describing resin-loading usingcalibrated NIR spectroscopic technology and principles of the inventionfor producing oriented strand lumber.

DETAILED DESCRIPTION OF INVENTION

Analyzing problems associated with continuous-type assembly-lineprocessing of wood materials and uncovering concepts for use ofspectroscopy, including calibrating near infrared (NIR) spectroscopicinstrumentation, contributed solutions capable of being carried outon-line to provide for quantitative measurement of resin-loading ofwood-materials while moving in-line for assembly and subsequent pressinginto composite wood product.

NIR spectroscopic quantitative analyses of resin-loading during in-linemovement for assembling wood-materials into composite had been unknown;and, correlating aspects of line operations, by feedback of measuringresults using calibrated NIR spectroscopic instrumentation, enablingquantitative resin-loading analyses during continuing-type in-linemovement and assembly of wood-materials for subsequent pressing intocomposite wood product.

For purposes of disclosure of those concepts in more detail, a specificembodiment of the invention will be described involving resin-loading ofmultiple individual layers, each formed from wood-strand materials asdescribed herein, is measured during in-line assembly for uniformresults.

The non-invasive on-line quantitative measurements of resin-loading ofthe invention enables production of composite wood-strand product whichis within desired manufacturing specifications; and, also, enablesproviding for on-line verification and control of resin-loading, whichis significant in continuous-line assembly of wood-strand materials bycontributing to uniform high-strength characteristics fororiented-strand products assembled, in accordance with the invention, asused for “I” joists, two-by-fours, other structural components, and forcomposite sheeting for floors, roofs and siding.

Use of the presently disclosed calibrated NIR spectroscopic measurementsenables timely determination of resin-loading during continuing in-linemovement of wood-materials as being assembled; and, for timely on-linemodifications of resin-loading to maintain desired standards. Thepresent principles of NIR spectroscopic measuring technology, duringassembly, can also contribute to verification of desired resin-loadingby measurements after heat and pressure bonding of composite-woodproduct.

FIG. 1 depicts apparatus for describing principles of the invention forcalibrating near infrared (NIR) spectroscopic measuring instrumentation.Such apparatus can provide for accurate quantitative analysis ofresin-loading under dynamic on-line assembly conditions; and, can beused for instruction, and training personnel for use of principles ofthe invention. The presentation of FIG. 2 is for describing steps forusing those principles in accomplishing desired calibration of NIRspectroscopic instrumentation. And, FIG. 3 graphically depictsachievement of resin-loading results, within manufacturing standards,when using calibration principles of the invention for quantitativemeasurement of resin-loading using near infrared (NIR) spectroscopy.

The apparatus of FIG. 1 can be used for calibrating NIR spectroscopicresin-loading measuring equipment off-line; or, for on-line calibrationin a dynamic process in which wood-materials are moving in a continuingassembly line.

Calibration concepts of the invention are disclosed in relation toassembly of strand-wood materials. In a specific embodiment for assemblyof oriented strand board (OSB), thin wood strands are cut from debarkedand otherwise prepared logs. Those thin strands have widths of about 0.5inch up to about two-inches, lengths of about four to about to sixinches, and thicknesses of about 0.02″ to 0.025″, as they are strand-cutor “flaked” for assembly of oriented strand board (OSB). A selectedthermosetting adhesive-type resin is applied to those light-weightstrands which are used in forming a plurality of individual strandlayers, of selected thickness, for assembly of OSB. The multiple strandlayers are subsequently bonded together using heat and pressure, into aunitary composite of wood-strand layers.

In calibrating the apparatus of FIG. 1 for quantitative analysis ofresin-loading of strand-wood materials, such as thin wood strands,reference-source test-samples are first accurately pre-established in aspecified order. Those reference-source test-samples, each presenting apre-established resin-loaded layer of strand-wood material, aresupported on a surface capable of providing movement at a selectedcontrolled rate.

The test-samples of the embodiment of FIG. 1 are supported on turntable20; and, turntable 20 is equipped to be capable of rotation so as tosimulate an on-line controlled-rate of linear movement of resin-loadedstrand-wood material. Preferably in the embodiment of FIG. 1,resin-loading of each individual reference-source test-sample ispre-established so as to produce incrementally differing resin-loadedpercentage weights; for example, at levels from about 3% to about 12%resin-weight with respect to the weight of respective reference-sourcetest-sample strand-wood material. Present principles can also be used inmeasuring resin-loading of wood-strand lumber in terms of spread-weightper unit area.

The test-samples are positioned on turntable 20 so as to be capable fora rate of movement which simulates a desired linear movement rate ofresin-loaded wood-materials when carrying out measurement ofresin-loading when carried out during assembly on-line. That is:rotation of turntable 20 of FIG. 1 enables correlation of test-samplemovement with the prospective rate of movement of wood-materials on aconveyance surface used for assembly of the strand-wood materialstraveling toward pressing apparatus bonding under heat and pressure.

Sensor head 22 includes a full-light spectrum lamp, for illuminatingtest-samples which is indicated by beam 24. In the specific embodiment,near infra-red (NIR) radiation source 26 provides for selecting of adesired range of radiation wavelengths within about 350 to about 2500nanometers (nm). A NIR radiation range, covering wavelengths from about400 nm to about 2250 nm, is selected for providing desired penetrationof wood-strand materials; and, for enabling quantitative analyses ofresin-loading by measuring reflective NIR energy after absorption of NIRby the strand-wood material.

Penetrating NIR energy, in the selected wavelength spectrum, is at leastpartially absorbed by the resin-loaded wood-strand material.Non-absorbed NIR energy, as return-reflected by wood-materials on theconveyance surface, is directed via fiber-optic cable 28, formeasurement, to monochromator 30.

The reflected NIR energy is measured in the selected range ofwavelengths from 400 nm to 2250 nm; however, absorptive effects specificto moisture content of the strand-wood material and moisture content ofthe loaded resin, are preferably selectively removed in the processingof the spectra data at wavelengths of 900-1000 nm, 1400-1500 nm, and1900-2000 nm. That calibration method provides for prompt computerdetermination of, and accurate quantitative analyses, of NIR absorptiondue to resin-loading of the wood-materials on the test-samples.

In a specific calibration embodiment, a thermosetting resin wasaccurately established for on OSB-strand wood test-samples, as indicatedat stage 32 of FIG. 2; resin-loading percentage weight levels wereestablished, as closely as practical, to approximately 3%, 6%, 9% and12%. Differing moisture level wood strands were used in respectivetest-samples, in order to verify that differing moisture-content of thewood-material does not effect accurate resin-loading measuring ability.The results achieved in measuring said known resin-loaded test-samplesverified the calibration method. The calibration for NIR spectroscopicquantitative analyses of resin-loading removes the absorptive effect ofconstituents other than resin; specifically, removing wavelengths ofmoisture-content of the strand-wood material and moisture content of theresin. That is accomplished, during processing as set forth above, byremoving moisture-content peak absorptive effects in wavelength bands of900-1000 nm, 1400-1500 nm, and 1900-2000 nm.

Rotating turntable 20 at twenty RPM with the sensor head NIR source lampfocused at a radius of ten inches from its center of rotation enabledsimulating a selected linear rate of movement for use in forming woodstrand layers in an assembly line. Position of sensor head 22 ispreferably selected in a range of about four to about ten inches abovethe samples.

In the calibration steps of FIG. 2, the test-samples are positioned forsupport on a movable surface, as indicated at stage 33; and, thefull-spectrum visible-light illumination and NIR radiation arecarried-out at stage 34. Return of non-absorbed NIR, as reflected fromwood-materials on the movable support surface, is indicated at stage 35.The selected range of wavelengths is monitored for return-reflected NIRradiation at stage 36. At stage 37, processing software, operating inaccord with the above-described calibration method, removes the effectof moisture constituents and provides a percentage weight measurementresponsive to the absorptive effect of resin-loading of the strand-woodmaterial.

To evaluate and verify the calibration method, known resin-weightpercentage levels for the test-samples were established as set forthabove and were measured while moving at the selected rate. Thosemeasurements with calibrated instrumentation, verified the linearrelationship between resin-loading and spectral data, which enablesmeeting desired manufacturing standards, as exemplified graphically inFIG. 3 in which NIR measured resin-loading is plotted versus actualpre-established resin-loading, see tabulation below. Pre-establishedresin-loading percentage weights are presented along the “x” axis,reference number 38 of FIG. 3; resin-loading percentage weights, asmeasured by calibrated NIR spectroscopy, are set forth along the “y”axis, reference 39 of FIG. 3.

Solid graph line 40 shows the algebraic linear relationship betweenresin-loading and spectral data; and, actual measurements are presentedby the square markings.

TABULATION: Actual NIR Measured Resin Loading Resin Loading 3.07 2.933.07 2.91 6.06 5.99 9.08 9.55 9.08 9.75 12.08 13.04The accuracy of resin-loading measurements is within manufacturingstandards, when measured by calibrated NIR spectroscopic instrumentationas described in relation to FIGS. 1 and 2. That result confirms thecalibration method based on removing the absorptive effects of moisturecontent.

Correlating NIR spectroscopic measurement calibration technology withon-line assembly in a continuing manner is described in relation to FIG.4. In that diagrammatic flow-chart wood-strand materials are formed intoa specific individual strand-board layer, such as a face-layer ofmulti-layer oriented strand board (OSB). Debarked logs are strand-cut todimensions, described above, at stage 41. The wood-strand material isaccumulated at station 42 and directed for entry into, and forcontrolled in-line movement through resin-loading 43. A liquid phenoliccan include powdered phenolic. However, phenolic resin in a liquid form,capable of being atomized, is preferred in the specific OSB embodimentdisclosure of the invention. A controlled amount of powdered phenoliccan be included in that embodiment.

Resin-loading for in-line assembly is carried out during passage throughfluidized-bed resin-loading stage 43. On-line calibration of theinstrumentation can be initiated at stage 44 of FIG. 4. The calibrationprocessing as described in relation to FIGS. 1, 2 and 3 above, can becarried-out by combining stages 44 and 45. That is, test-samples ofknown resin-loading are established at station 44; the describedcalibration method, involving removal of moisture content spectra forproviding prompt on-line NIR measurement of resin-loading, withinmanufacturing standards, can be provided on-line and periodicallyverified. Calibrated NIR instrumentation measurement of resin-loading iscarried out at in-line measurement station 46.

During assembly, resin-loaded wood strands, from fluidized bed 43, areplaced on an in-line conveyor surface at station 47. Said conveyor ismoving at a rate coordinated with the controlled-rate of movement ofwood-material, through fluidized-bed resin-loading station 43.Resin-loaded wood strands, moving on the conveyor-surface of station 47,are illuminated by visible-light and irradiated by NIR source aredirected, as indicated by interrupted line 48, from measurement station46. And, return-reflected NIR energy is directed along interrupted line49 for calibrated NIR instrumentation measurement of resin-loading atmeasurement station 46.

Use of the calibration method, as described, enables measurement ofresin content during assembly-line linear movement of wood-material ofunknown moisture levels and unknown resin percentage weight. Incalibration method return-reflected NIR energy is directed, as indicatedby interrupted line 49, for removal of absorptive effects, of moisturespectra at station 46. The resulting calibrated-measurement of resinloading weight is directed, as indicated by interrupted line 50, fordisplay at station 52. In FIG. 4, resin-loading of the individual woodstrand layer is measured in-line, on a moving conveyor, and is displayedat station 52.

The resin-loading data of display station 52 enables control of desiredresin-loading during on-line assembly. Metering of prepared resin can becarried out at station 54. Resin-loading for wood strands, for forming aface-layer of an oriented-strand board (OSB), can be selected, forexample, at a weight of three percent (3%); in that example:resin-loading by weight is 3% of the wood-strand material moving throughfluidized bed resin-loading station 43. The resin-loading value displayat station 52 enables control of resin-loading of the wood strand whilemoving at a controlled rate through resin-loading-bed 43. A selectedrate of resin-loading, can be maintained utilizing proper resin meteringat metering station 54 and/or proper movement of the wood-strandmaterial through fluidized bed resin-loading stage 43.

During line operations, observing the calibrated NIR spectroscopicquantitatively measured resin-loading data at station 52, enablesdiminishing or increasing the metering rate of the resin at station 54;or, diminishing or increasing the movement rate of the wood atfluidized-bed resin-loading station 43, in order to maintain acontinuing desired resin-loading value for in-line assembly of astrand-layer. The prompt and accurate measurement, with display ofresin-loading, enables on-line control which helps to maintaincontinuing assembly within manufacturing standards.

FIG. 5 is presented for describing the type of equipment utilized forforming, on-line, an individual strand-layer for oriented strand-board(OSB). Prepared and debarked logs, from station 58, are directed forselected stranding for a strand-layer, at stage 59. Preferably, strandsare washed at 60; and, are at least partially dried for accumulation atstation 61 for in-line usage. Strands are directed at a controlled-rate,measured in weight of strands per unit time, for in-line movementthrough a fluidized resin-loader 62.

Phenolic resin is prepared for metering at station 64. Metering iscontrolled to maintain a selected resin percentage weight, which can beabout three percent (3%) of the weight of wood strands for a face layerof oriented strand board (OSB). The movement rate of wood strand throughresin-loader 62, as measured in weight per unit time, can be increasedor decreased as correlated with the resin metering rate. Liquidphenol-formaldehyde (PF) is atomized in a specific embodiment of theinvention. Resin-loader 62 defines a specific internal volume for afluidized-bed of resin; strands from station 61 are directed into,through, and out of resin-loader 62 at an in-line controlled rate whichis measured in terms of movement of a specific weight of strands perunit time.

A tumbling action for thin strands in resin-loader 62 facilitatesuniform resin-loading of individual strands with atomized resin frommetering station 64, as resin is introduced at controlled ratecorrelated with movement rates of the strands. The strand movement ratecan be maintained at a constant level during operations by control ofthe resin-metering rate.

From resin-loader 62, the resin-loaded wood strands are directed forforming strand layer 66; that layer is indicated by interrupted lines,on the moving surface of forming conveyor 68. NIR source and sensor head70 provide for illuminating the strand-layer as assembled and forirradiating with NIR in a selected range of wavelengths. Reflectingnon-absorbed NIR radiation is measured at calibrated sensor 70 and thatmeasurement is directed, as indicated by interrupted line 71, toresin-loading indicator 72. That indicated value is used for control ofresin-loading should an indicated value vary from a selected desiredresin-loading; for example, by feedback control over interrupted line 73to resin metering station 64.

Steps and equipment for multiple-layer OSB specific embodiment of theinvention are described in relation to FIG. 6; in which individuallayers of the multiple layers selected, are assembled and directed forbonding into composite oriented strand board. Individual strand layerscan differ in thickness, and other aspects, as tabulated later herein.The face layers, located on opposite planar surfaces of a centralizedcore layer, can include a wax for moisture resistence; also, the resinselected for the core layer can differ from that for the face layers.

Face layer strand is fed from station 74 of FIG. 6, at a controlledrate, in weight per unit time, into flulidized-bed resin loader 75 whichdefines a volume for feeding at a specified rate. Resin is metered at acontrolled rate from station 76, to achieve desired resin-loading,within a desired manufacturing specifications. Resin-loaded strands aredirected to first conveyor 77 forming resin-loaded face-strand layer 78.That resin-loading is measured by near infrared (NIR) spectroscopicequipment 79, which is calibrated as described above. Resin-loadedpercentage weight is directed to display 80. Feedback signal-line 81provides for promptly correcting percentage resin-metering to maintainmanufacturing specifications.

Strands for central core layer are directed from station 82, asindicted, to core-layer fluidized-bed resin-loader 84. The resin for thecore layer can differ from the phenol-formaldehyde used for theface-layers; as set forth later. Core-layer resin is metered at station85 and directed, as indicated to resin-loader 84, so as to maintainresin-loading metering within manufacturing specifications.

Resin-loaded core strands are directed, as indicated, from station 84,to form core-strand layer 86 on the moving surface of conveyor 87.Resin-loading for the core layer 86 is measured by calibrated NIRspectroscopic equipment 89, as described earlier; and, the percentageweight is displayed at indicator 90. Feedback line 91, to core-resinmetering station 85, enables any deviation from a desired core resinpercentage weight to be corrected promptly.

Simultaneously, with forming of the above-described face layer and corelayer, strand for a remaining face strand layer is directed from station92, as indicated, to face-layer fluidized-bed resin loader 94, whichprovides for in-line movement of strand at a selected controlled rate.Face-layer resin metering is carried out at station 95. Resin-loadedstrands are directed, as indicated, to form face-layer 96 on conveyancesurface 97, which is moving as indicated.

Resin-loading of face layer 96 is quantitatively analyzed by calibratedNIR spectroscopic equipment 99; that percentage weight measurementresult is directed to display 100, as indicated, correction ofpercentage weight resin-loading, if required, can be promptly directedvia feedback line 101 to metering station 95; for maximizing productionwithin desired standards.

Assembly of the individual strand layers is carried out via theindividual moving conveyors 77, 87, and 97. Resin-loaded face strandlayer 78, moves from conveyor 77 to conveyor surface 102, moving asindicated. The core strand layer 86 moves onto the face-layer beingconveyed by conveyor surface 102, as indicated. And, the remaining facelayer 96 moves onto the remaining surface of the core layer 86. Thethree resin-loaded layers are combined as conveyor 102 and indicated at104 of FIG. 6; the multiple assembled layers are directed to station 105for bonding utilizing heat and pressure values, as tabulated laterherein.

The number of layers in oriented strand board (OSB) can be selected.FIGS. 7 and 8 present respectively a top plan view and a side elevationview of a sample portion of three-strand oriented strand board (OSB) asassembled in accordance with the invention, and bonded using heat andpressure.

The top plan view of FIG. 7 depicts the differing orientations of theelongated thin strands; note, for example, strand 107 and strand 108 insurface 109. The front-elevation view of FIG. 8 depicts thickness offace layer 110, central core layer 112, and remaining face layer 114.The strands of the central core layer 112 can be selectively orientedin-line with the elongated dimension of assembly; that is, strands in acentral core can be selectively oriented more uni-directionally than ina face layer.

The multiple directional orientations of elongated thin strands of themultiple layers contribute to structural strength characteristics of theOSB; and, help to prevent bending during use, for example, of four byeight (4′×8′) panels extending between structural supports. Control ofresin-loading, during assembly, as described above, helps to provide anengineered composite wood-strand product with consistent high-strengthproperties for structural uses. OSB thickness (shown in FIG. 8) can beselected in a range of above about one fourth inch (above about sevenmm) to about three quarters inch (nineteen mm); as set forth in thefollowing tabulated data.

TABLE ORIENTED STRAND BOARD Overall Thickness above ¼″ to about ¾″(about 0.7 to about 19 mm) Each Face Strand (thickness) about 0.125″(0.635 mm) to about 0.1875″ (4.445 mm) Core Strand Layer Thickness about0.322″ (8.1 mm) to about 0.45″ (11.4 mm) Face Strand Layer Resinphenol-formaldehyde (phenolic) Core Strand Layer Resin isocyanates orphenolics Curing: Loose layers of the resin-loaded thin wood strands arecompressed under pressure at temperature(s) of about 350° F. to 400° F.(177° C. to 204° C.), for about three to five minutes. Source for NIRSpectroscopy FOSS NIRSystems, Inc. Equipment 12101 Tech Road SilverSpring, MD 20904 USA Source for Resin Dynea U.S.A., Inc. 1600 ValleyRiver Drive Suite 390 Eugene, OR 97401 USA

Principles of the invention, as described in detail in relation tooriented strand board (OSB), also extend to assembly of other woodstrand products. Another composite wood strand product, described below,is referred to as oriented-strand-lumber (OSL). Oriented-strand-lumberutilizes more precise stranding of elongated strands of increasedthickness than those for oriented-strand board (OSB). For example,strands for OSL can have a thickness of about 0.4 inch to about 0.5 inch(about 10 mm to about 12.5 mm); and, spread-weight measuring ofresin-loading is carried out in accordance with present principles.

FIG. 9 presents a perspective view of an end-usage product of bondedoriented strand lumber (OSL). OSL is assembled in an extended surfacearea mat from which various products can be cut during finishing. Thebonded multiple strands of the finished product of FIG. 9, from topstrand 116, through strands 117, 118 and 119, to bottom strand 120,include intermediate resin-loading, as measured and applied as spreadweight, in accordance with principles of the invention. Use of theabove-described calibrated NTR spectroscopic resin-loading principlesprovides for prompt measuring; and, helps to maintain uniformity ofresin-loading spread weight for assembly of an extended surface-areamat, as set forth above.

FIG. 9 depicts a finished product, such as a “two by four” stud cut froman extended surface area mat. Five strand-lumber layers, with measuredresin-loading are assembled in a large surface area mat, and then bondedby heat and pressure to form composite OSL. Four or five layers ofstrand lumber can be used in assembly of an extended area mat Arepresentative total thickness can be extended from about 1.75 inches(about 44.5 mm) to about two inches (about 50 mm). The thickness for anindividual strand lumber layer can be about 0.35 inch (about 9 mm) toabout 0.4 inch (about ten mm).

Phenol-formaldehyde (PF) resins, are spray-coated on the strand lumber,and measured for resin spread-weight per unit area, for assembly ofwood-strand lumber. Bonding is carried out in a temperature range as setforth earlier for phenolic. The length and width dimensions forindividual lumber wood strands can be selected for particular end usage;and strands can be inter-fitted in forming an extend surface-area mat.After bonding, finish end-usage product can be cut, such as studs andmillwork.

Specific materials, dimensions, percentages, and other values have beenset forth for purposes of describing specific embodiments which enableone skilled in the art to make and use the invention. However, it shouldbe recognized that the above disclosures of embodiments include specificdescriptions of materials, combinations, percentages, dimensions, andother values, which, in the light of the above disclosure, can enableone skilled in the art to make changes in those specified values, whilecontinuing to rely on the principles of the invention as disclosed.Therefore, in evaluating valid patent coverage, for the disclosedsubject matter, reference should be made to the appended claims; and,the language of those claims should be construed in the light of theabove disclosures.

1. Method for calibrating near infrared (NIR) spectroscopicinstrumentation so as to enable use in quantitative measurement ofresin-loading of wood-materials during in-line assembly for subsequentbonding during production of a composite wood-product, comprising (A)providing NIR spectroscopic instrumentation including an associatedsource of NIR radiation covering a range of wavelengths selected withinabout 350 nm to about 2500 nm; (B) quantitatively pre-establishingresin-loading of reference-source test-samples of wood-materials of atype selected for in-line assembly, and capable of providing for bondingto produce a composite wood-product; (C) supporting said pre-establishedresin-loaded test-samples on a conveyance surface capable ofestablishing a controlled rate of relative movement between saidsupported test-samples and said source of NIR radiation for irradiatingwood-materials of said test-samples; (D) establishing said controlledrate of relative movement for said test-samples simulating a selectedin-line controlled-rate of movement of resin-loaded wood-materials beingdirected in-line for assembly; (E) irradiating said pre-establishedresin-content test-samples with NIR radiation, covering said selectedrange of wavelengths, during relative movement between said NIR sourceand said test samples at a selected controlled rate for quantitativemeasurement of absorption of said NIR radiation of said wood-materialsof said pre-established resin-content test-samples; (F) calibrating saidspectroscopic instrumentation by providing a calibration curve enablingquantitative analyses of resin-loading of test-sample during saidcontrolled movement of said test samples, by measuring non-absorbed NIRenergy within said selected range of wavelengths as reflected by saidexposed test-samples on said conveyance surface; and (G) removing theabsorptive effect of said reflected NIR energy resulting from NIRabsorption by constituents of said test samples other than resin.
 2. Theinvention of claim 1, including establishing resin-content of saidtest-samples so as to present an incrementally-progressive resin-loadingfor wood-materials of respective test-samples, with said resin-loadingbeing selected from the group, consisting of: (i) a spread weight perunit area, and (ii) percentage weight of resin to weight of woodmaterials, extending in a range of zero percent to about fourteen (14%)percent.
 3. The invention of claim 1, in which relative movement isestablished between said test-samples and said source of NIR, includingsteps of selecting a rotatable conveyance surface capable of beingdriven at a rotational rate to simulate a selected in-line movement ratefor resin-loading of said type wood-materials of test-samples duringin-line assembly of said wood-materials, and for measuring reflected NIRenergy from wood materials of said resin-loaded test-samples.
 4. Theinvention of claim 1, in which providing a calibration curve for saidNIR spectroscopic instrumentation, includes removing absorptive effectsresponsive to moisture content of said wood-materials and of said resin.5. The invention of claim 4, including obtaining calibrated measurement,in a selected wavelength range of about 400 nm to about 2250 nm, ofresin-content of said test-samples by removing measured non-absorbedreflected NIR energy at wavelengths of: 900 nm to 1000 nm, 1450 nm to1500 nm, and 1900 nm to 2000 nm.
 6. Method for calibrating near infrared(NIR) spectroscopic instrumentation for non-invasive measurement ofresin-loading of wood-materials during movement in-line for assembly andsubsequent bonding for production of composite wood-strand product,comprising the steps of (A) preparing said wood-materials bystrand-cutting wood strands having a high length-to-thickness ratio andselected surface-area dimension parameters, for in-line resin-loadingand subsequent production of composite wood-strand product; (B)providing near infrared (NIR) spectroscopic measuring instrumentationincluding a sensor head and a source of NIR radiation, for irradiatingsaid wood-materials, in a range of wavelengths selected within about 350nm to about 2500 nm; (C) calibrating said NIR spectroscopic measuringinstrumentation for use in quantitative analyses of resin-loading ofsaid wood-materials during movement in an assembly line, by (i)preparing reference-source test-samples from said wood-materials,including: (a) pre-establishing resin-loading of said test-samples; (b)quantitatively pre-selecting resin-loading for said wood-materialsproviding an incrementally-increasing resin-loading of wood-materials ofsaid test-samples within a selected resin-loading range, and (c)positioning said pre-established resin-loaded test-samples on a conveyorsurface capable for use during assembly of said cut wood strandmaterials; (D) positioning said spectroscopic measuring instrumentation,and said NIR source, for (i) irradiating said test-samples, and (ii)providing penetration of, and at least partial absorption by, saidresin-loaded test-samples of said NIR radiation within said selectedrange of wavelengths: and (E) calibrating said NIR spectroscopicinstrumentation, by (i) measuring non-absorbed NIR energy as reflectedby said wood-strand materials of said test-samples, (ii) comparing saidcalibrated absorbed NIR spectroscopic absorptive measurements of saidincrementally-increasing pre-established resin-loading test-samples,with (iii) said pre-established resin-loading of wood-strand materialsof said respective test-samples for verifying accurate calibrating ofsaid instrumentation for measurement of resin-loading, and (iv)selectively removing NIR absorptive effects due to moisture-content ofsaid wood test-samples and of said resin.
 7. The invention of claim 6,further including (F) providing for in-line use of said calibrated NIRspectroscopic measuring instrumentation for non-invasive measuring ofresin-loading of wood-strand materials moving in an assembly line forsubsequent bonding-treatment production of composite wood-strandproduct, selected from the group consisting of: (i) oriented strandboard, and (ii) oriented strand lumber.
 8. The invention of claim 7 forproduction of oriented strand board (OSB), carried out by controllingrate of movement of said wood-strand materials through a resin-loadingstructure, and correlating introduction of resin with rate of movementof said wood-strand materials so as to control resin-loading weight. 9.The invention of claim 8, further including (H) establishing a rate ofmovement for resin-loaded wood-strand materials onto a strand-layerforming conveyor surface which is moving at a rate correlated with saidcalibrated NIR spectroscopic instrumentation for measurement ofresin-loading; (I) utilizing said calibrated NIR spectroscopicinstrumentation for quantitatively-monitoring resin-loading ofwood-strand materials, by (i) measuring resin-loading of saidresin-loaded wood-strand materials, as delivered from said resin-loadingstructure, while moving on said strand-layer-forming conveyor, and (ii)indicating said measured resin-loading of raw said wood-strand materialsso as to be available for control of assembly operations for purposes ofcontrolling resin-loading.
 10. The invention of claim 9, furtherincluding: (J) providing for quantitative-control of said resin-loadingby (i) indicating resin-loading value as measured by said NIR calibratedinstrumentation, for (ii) feedback control of resin-loading, by (iii)selecting from the group consisting of (a) quantitatively controllingresin as introduced for contact with said strand materials, (b)controlling rate of movement of said strand materials being deliveredfor said assembly line, and (c) combinations of (a) and (b), for (iv)maintaining a desired uniform resin-loading weight in relation to weightof said wood-strands during strand layer forming assembly.
 11. Theinvention of claim 10, including providing multiple separate movablestrand-layer conveyor assembly surfaces for assembly of planar strandlayers selected from the group consisting of (i) three-strand layers,and (ii) five-strand layers.
 12. The invention of claim 11, for assemblyof oriented strand board of three-strand layers, each strand layerreceiving wood-strand materials at a controlled rate for separatelyforming: (i) a face layer, (ii) a core-layer, and (iii) a remaining facelayer.
 13. The invention of claim 12, further including selectingrespective resin and resin-loading percentage weight for each saidseparate layer; controlling resin-loading for each said separatestrand-layer while moving on its respective conveyor surface, andcombining said multiple planar layers by: (i) positioning a resin-loadedface layer on each planar surface of said centrally-located resin-loadedcore-layer, for (ii) pressing said combined wood-strand layers by timedexposure to heat and pressure, for (iii) polymerizing said controlledresin-loaded combined layers, producing said composite oriented woodboard.
 14. The invention of claim 6 for production of oriented strandlumber (OSL), comprising selecting strand lumber having a highlength-to-thickness ratio, controlling resin-loading of said strandlumber using NIR calibrated spectroscopic measurement of resin loading,combining said resin-loaded strand lumber forming an enlarged mat forpressing under heat and pressure, and finishing said bonded mat bycutting said mat into end-usage product selected from the groupconsisting of (a) structural studs, and (b) millwork components.